#include <cstdio>
using namespace std;
const int CLK_TCK = 100;

int main(){
	int c1, c2;
	scanf("%d%d",&c1,&c2);
	int ans = c2 - c1;
	if(ans % CLK_TCK >= 50){
		ans = ans/CLK_TCK + 1;
	}else{
		ans = ans/CLK_TCK;
	}
	printf("%d:%d:%d",ans/3600,ans%3600/60,ans%60);
	return 0;
}
